In recent years, of a wireless chip including a plurality of circuits and an antenna has been developed. Such a wireless chip is referred to as an ID tag, an IC tag, an IC chip, an RF (Radio Frequency) tag, a wireless tag, an electronic tag, an REID (Radio Frequency IDentification) tag, or the like and has already been introduced into some markets.
Many of these wireless chips which are currently in practical use have circuits using semiconductor substrates of silicon or the like (such circuits are also referred to as IC (Integrated Circuit) chips) and antennas. The antenna is formed by a printing method, a method in which a conductive thin film is etched, a plating method, or the like (for example, Patent Document 1: Japanese Patent Application Laid-Open No. H9-1970).
The antenna formed by the above method is a thin film or a thick film. The antenna attached to a flexible material such as paper or plastic has a problem in that the antenna is sensitive to bending or folding, so that a part of the antenna is easily broken.
Moreover, in the case of a wireless chip formed using a semiconductor substrate, the semiconductor substrate serves as a conductor and blocks for an electric wave; therefore, there is a problem that a signal is easily attenuated depending on the direction of a signal which is sent.